LIDAR Mirror Center Shift for Distance Accuracy
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Solution Overview
Problem
Existing LIDAR devices face challenges in accurately calculating distances to objects due to variations in rotational speed of the scanning mirror during scanning, leading to inconsistencies in laser beam emission and reception timing, which affects the accuracy of distance measurement.
Innovation Solution
The LIDAR device employs a scanning mirror arrangement where the mirror center shifts within a defined motion area as it rotates between positions, ensuring the light beam center aligns with the mirror center at one position and reflects at edge portions at other positions, using an angle sensor to control laser emission at precise rotation angles, and a digital light receiver for high-resolution detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the scanning mirror rotates to scan the entire scanning zone, then the scanning coverage is improved, but the rotational speed varies causing timing inconsistencies and reducing measurement precision
Solution Approach 1:
The patent changes the parameter of mirror center position from fixed to variable. By allowing the mirror center to shift within a defined motion area during rotation, the system compensates for rotational speed variations. This parameter change enables consistent distance measurement across different scanning positions while maintaining full scanning zone coverage.
2Device complexity
If the mirror center is fixed during rotation, then the structure is simpler, but the distance measurement accuracy decreases due to rotational speed variations
Solution Approach 1:
The patent applies dynamics by making the mirror center position variable rather than fixed. The mirror center dynamically shifts within the motion area during rotation to compensate for speed variations. This dynamic adjustment improves measurement precision without requiring complex additional positioning mechanisms, as the shift is achieved through the existing rotational mechanism.
3Measurement precision
If the light beam center is always aligned with the mirror center, then the scanning consistency is improved, but the device size increases to accommodate the alignment mechanism
Solution Approach 1:
Instead of aligning the light beam center with the mirror center through complex mechanisms, the patent inverts the approach by allowing the mirror center to shift to meet the light beam center. This inversion simplifies the system and reduces device size, as the mirror's natural rotation and the defined motion area enable alignment without additional bulky components.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration allows for accurate and consistent scanning across the scanning zone, reducing the size of the device and enhancing measurement accuracy by compensating for rotational speed variations and time lag errors, resulting in precise distance calculations without the need for a separate processor.
Implementation Method 1
The mirror has a reflective surface and a back surface opposite to the reflective surface. The mirror is configured to reflect, with the reflective surface, the light beam emitted from the light source toward the scanning zone.
Data Source
AI summary
A LIDAR device includes a light source, a mirror, a rotatable shaft, and a motor. The light source configured to emit a light beam having a predetermined light beam width for scanning a scanning zone. The rotatable shaft has a center axis parallel to a reflective surface of the mirror and is connected to a back surface of the mirror. The motor is configured to rotate the shaft to cause the mirror to swing between a first position and a second position. The light source and the mirror are arranged to have a positional relationship such that a mirror center is aligned with the light beam center when the mirror is at the first position, and the mirror center shifts within a motion area when the mirror is swinging between the first position, non-inclusive, and the second position, inclusive.